Biosynthesis of Insulin by the Isolated Perfused Dog Pancreas

Evidence is presented to show that the isolated, perfused dog pancreas is capable of incorporating C-14 labeled amino acids into fractions that have immunologically reactive and biologically effective insulin activity. The perfusion medium was recirculated through the pancreas from a reservoir for four hours. At the end of the perfusion, the pancreas, gut segment and medium were individually extracted and the active fractions separated on a Sephadex column. Each fraction was tested using the two antibody assay of Hales and Handle and the hemidiaphragm and fat pad assays. Peak 2 of the pancreas consistently had the greatest amount of IRI, ILA, and C-14 radioactivity. The in-corporation of C-14 amino acids into the fraction with ILA and IRI appeared to be an energy requiring process since 2,4-dinitrophenol completely blocked the appearance of C- 14 into the active fractions. It is concluded that the feasibility of the use of this preparation for studying of pancreatic hormones is demonstrated.